This invention relates to a method and apparatus for depositing articles, in particularly seeds. More particularly, it relates to improvements in cassettes for sowing seeds.
Many plants, especially flowers and vegetables as well as many trees, are first grown as seedlings in greenhouses in small containers before being transplanted into larger containers or in the ground. Usually one or two seeds are planted in a small container which carries nutrients for growth. Normally the containers are connected together in a matrix called a seedling tray.
The procedure for sowing seeds in seedling trays has been largely mechanized. One mechanized apparatus is disclosed in U.S. Pat. No. 4,221,175 issued to Aart Van Wingerden et al. The Van Wingerden Patent teaches the use of a tray having a plurality of embossments therein with each embossment receiving a seed. The tray is covered by a plate having a matrix of holes which align with the embossments in the tray. Between the tray and the plate are a number of rods each of which has a plurality of holes there through. The rods block the movement of the seeds out of the embossments while the apparatus is in one position; however the tray and plate are adapted to be rotated 180.degree. contacting an apparatus which includes a plurality of tubes extending into the tops of each container of a seedling tray. Once this inversion takes place the rods may be rotated 90.degree. so that the holes in the container and plate will align with the holes in the rods thereby permitting the seeds to pass through into the tubes and into the seedling tray.
While the Van Wingerden Patent represents an early mechanization of the planting process, the apparatus disclosed therein is somewhat complicated and is slow in operation. More recently a cassette has been developed by Van Wingerden which is shown in FIGS. 1 and 2.
The Van Wingerden cassette 10 utilizes a plurality of plates 12 which are stacked one upon another. Contact between adjacent plates is made by means of raised rim 14 as shown in FIG. 1. Studs 16 snap into corresponding holes (not shown) on the bottom side of the adjacent plate. A plurality of perforations 18 are received in each plate 12. The perforation receiving portion 20 of the plate is slightly recessed from rim 14. The recess is provided to accommodate blocking paper layer 22 which is slidably received between each adjacent plate.
The perforations in each plate except for the bottom plate 24 are adapted to receive a seed 26. The cassette is adapted to be placed on the top of seed distribution means 28 which is shown in FIG. 5.
The perforations 30 of the bottom plate align with holes 32 of the distribution means. When it is time to plant the seeds in trays 34, the lowermost paper 36 is removed from its position between the adjacent plates and the seeds from plate 38 will pass through perforations 30 in plate 24 through holes 32 in distribution means 28 through tubes 40 and are planted in containers 34. Once the container 33 is fully planted a new container is placed under tubes 40 and the next paper 42 which is the one just above paper 36 is removed from its position between adjacent plates and another group of seeds are planted. This process continues until all of the seeds in cassette 10 have been planted.
While the Van Wingerden cassette utilizing the blocking paper technique represents a simplification and improvement over the Van Wingerden seeding technique set forth in U.S. Pat. No. 4,221,175 this technique is not without its problems. It has been found that in moving the paper between the plastic plates, static electricity is formed, provides an attraction between the plastic plates and seeds, often causing the seeds to stick in the cassette.
Furthermore, it has been found that as the paper is pulled out, the seed moves with the paper and often becomes wedged between plates.
Another problem occurs in manufacturing the plates and the paper. Very close tolerances are required for the dimensions of the paper and recessed portion 20 over which paper 22 is received. When the paper or recess is somewhat out of specification it is very difficult to place the paper in the cassette as well as pull it out of the cassette.